The present invention relates to a semiconductor memory and a memory system, and relates to, for example, a semiconductor memory capable of selecting a separate IO (SIO) mode and a common IO (CIO) mode when data is input or output and a memory system using this semiconductor memory.
A data input/output mode of a semiconductor memory includes a common IO mode (hereinafter it will be referred to as a CIO mode) in which input or output of data is performed using a common terminal (common IO) and a separate IO mode (hereinafter it will be referred to as an SIO mode) in which input or output of data is performed using a separate IO including a terminal dedicated for inputting data (dedicated input terminal) and a terminal dedicated for outputting data (dedicated output terminal). Japanese Unexamined Patent Application Publication No. 2005-235248 (Patent Literature 1) discloses a semiconductor memory capable of switching the CIO mode and the SIO mode according to a mode control signal.